Highways Agency contractors are currently replacing waterproofing at the Gravelly Hill Interchange in Birmingham, commonly known as Spaghetti Junction.
However, engineers have found clusters of damage around loadbearing supports and joints – the location of which will make the necessary repairs challenging.the Agency said. In some areas, water has breached the old waterproofing, damaged the concrete deck and corroded the internal steel reinforcement.
It is now expected to take until spring 2016 to complete the repairs.
“We expected to carry out concrete repairs as part of this work,” explained project manager Jess Kenny. “But we were also aware that we wouldn’t know the full extent of what needed doing until we began the work and were able to remove areas of the road surface.
“Unfortunately, we’ve now discovered that the location of the damage is such that the repairs will be more extensive and take longer than at first thought, so the work won’t be completed until next year.”
As part of the re-waterproofing project, it was estimated around 2.5% of the concrete carriageways of Spaghetti Junction would need repairs. This has turned out to be the case, but the problem now isn’t the scale of the damage – it’s the location. Engineers will have to tackle the repairs in small sections, as the integrity of the bridge structure would be compromised if large areas of concrete are removed.
Jess Kenny added: “We’d love to be able to pull up all the surfacing and complete this work in one go: but that would seriously weaken the integrity of the bridge deck and cause a real threat that the structural stability of the bridge will be compromised. We’ve had to perform a lot of calculations to accurately work out how we can perform these repairs. The outcome is that we need several small phases of work – but this will also extend the time we need to work on Spaghetti Junction.”